Mingw friendly case for includes.

[mefyl]

Since windows filesystem is case insensitive and, AFAIK, windows.h is always lowercase in MinGW distributions, using a lowercase include will work on both transparently.

Currently:

mc_getrandom_stubs.c:60:10: fatal error: Windows.h: No such file or directory
   60 | #include <Windows.h>
      |          ^~~~~~~~~~~

[hannesm]

Thanks for your PR. By chance, would you be able to add a GitHub action (or another CI) that tests the "mingw" case?

[mefyl]

I'm not really familiar with Github actions; is there already a CI environment cross compiling with mingw ?

[hannesm]

I'm not really familiar with Github actions; is there already a CI environment cross compiling with mingw ?

I don't know. Maybe ask the people who're into "windows" and "OCaml" - they must have some secret runes how to test their projects in CI / GitHub actions.